#define _CRT_SECURE_NO_WARNINGS 1
#include <iostream>
using namespace std;
int s = 1;
int i = 1;
int sum(int n)
{
    int m = s;
    if (i == 1)
    {
        for (; i <= n; i++)
        {
            s *= i;
        }
        m = s;
    }
    else
    {
        s /= (n + 1);
        m = s;
    }
    if (n == 1)
        return m;
    else
    {
        return m + sum(n - 1);
    }
}
int main()
{
    int n;
    cin >> n;
    int t = sum(n);
    cout << t << endl;
    return 0;
}